xref: /freebsd/lib/libc/stdio/ungetwc.c (revision 22cf89c938886d14f5796fc49f9f020c23ea8eaf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2002-2004 Tim J. Robbins.
5  * All rights reserved.
6  *
7  * Copyright (c) 2011 The FreeBSD Foundation
8  *
9  * Portions of this software were developed by David Chisnall
10  * under sponsorship from the FreeBSD Foundation.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 #include "namespace.h"
36 #include <errno.h>
37 #include <limits.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <wchar.h>
41 #include "un-namespace.h"
42 #include "libc_private.h"
43 #include "local.h"
44 #include "mblocal.h"
45 #include "xlocale_private.h"
46 
47 /*
48  * Non-MT-safe version.
49  */
50 wint_t
51 __ungetwc(wint_t wc, FILE *fp, locale_t locale)
52 {
53 	char buf[MB_LEN_MAX];
54 	size_t len;
55 	struct xlocale_ctype *l = XLOCALE_CTYPE(locale);
56 
57 	if (wc == WEOF)
58 		return (WEOF);
59 	if ((len = l->__wcrtomb(buf, wc, &fp->_mbstate)) == (size_t)-1) {
60 		fp->_flags |= __SERR;
61 		return (WEOF);
62 	}
63 	while (len-- != 0)
64 		if (__ungetc((unsigned char)buf[len], fp) == EOF)
65 			return (WEOF);
66 
67 	return (wc);
68 }
69 
70 /*
71  * MT-safe version.
72  */
73 wint_t
74 ungetwc_l(wint_t wc, FILE *fp, locale_t locale)
75 {
76 	wint_t r;
77 	FIX_LOCALE(locale);
78 
79 	FLOCKFILE_CANCELSAFE(fp);
80 	ORIENT(fp, 1);
81 	r = __ungetwc(wc, fp, locale);
82 	FUNLOCKFILE_CANCELSAFE();
83 
84 	return (r);
85 }
86 wint_t
87 ungetwc(wint_t wc, FILE *fp)
88 {
89 	return ungetwc_l(wc, fp, __get_locale());
90 }
91